[flang][semantics] fix issue with equality of min/max in module files (#145824)
Convert all binary calls of min/max to extremum operations, so that
extremums generated by the compiler compare equal, and user min/max
calls also compare equal.
Fixes #133646
Originally opened as #144162 but I accidentally pushed a merge in such a
way that a bunch of code owners got added to the review. This is just
rebasing the original work on main and fixing the failing tests.